摘要
利用NCEP/NCAR再分析资料 ,探讨夏季东亚大气环流、大气视热源和视水汽汇的年际及年代际变化与登陆中国台风频数的关系。研究表明 :夏季 2 0 0hPa风场上南亚高压中心位置偏北 (南 )其形态表现向东北 (东南 )伸展 ,西太平洋热带地区上空 ( 2 0 0hPa)的东风急流加强 (减弱 ) ,中层 ( 5 0 0hPa)西太平洋副热带高压脊线位置偏北 (南 ) ,低层 ( 85 0hPa)东亚夏季风环流偏强 (弱 ) ,登陆中国台风数偏多 (少 )。夏季东亚—西太平洋热带大气视热源和视水汽汇为正 (负 )距平 ,即东亚热带大气出现辐射加热 (冷却 )和变湿 (变干 ) ,登陆中国台风数偏多 (少 )。 2 0世纪 5 0～ 60年代登陆中国台风频数处于年代际变化相对偏少期 ,70～ 90年代中期登陆中国台风频数处于年代际变化相对偏多期。夏季登陆中国台风频数的年代际变化与西太平洋热带大气视热源、视水汽汇及西太平洋热带海温的年代际变化一致 ,西太平洋热带大气视热源、视水汽汇及西太平洋热带海温处在年代际变化的低 (高 )值阶段时 ,夏季登陆中国台风频数也处在年代际变化的偏少 (多 )期。
The interannual and interdecadal variations of the landing typhoon frequency over China during summer were associated with the intensity of East Asian summer monsoon circulation, the positions of the subtropical anticyclone over the western pacific, the situation of South Asian Anticyclone at 200 hPa, and the variations of the tropical atmospheric heat (Q 1) and moisture (Q 2) source. The total number of the landing typhoon over China during summer was above (below) normal while the intensity of East Asian summer monsoon circulation strengthened (weakened), the ridge-line of subtropical anticyclone over the western Pacific was northward (southward) than the normal and the easterly wind over the region (120～160°E,5～15°N ) at 200 hPa became stronger (weaker). The interdecadal variation of the tropical atmospheric heat (Q 1) and moisture (Q 2) source over East Asia in summer occurred around in 1975. It was pointed that the interdecadal variation of tropical atmospheric heat (Q 1) and moisture (Q 2) source over East Asia during summer was associated with the interdecadal variation of SST at tropic of the western Pacific (120～150°E,5～20°N ).
出处
《大气科学》
CSCD
北大核心
2003年第1期97-106,共10页
Chinese Journal of Atmospheric Sciences
基金
中国科学院资源环境领域知识创新工程重要方向项目KZCX2 -2 0 3资助
